Gasoline compositions

ABSTRACT

A METHOD OF REDUCING INTAKE VALUE DEPOSITS FORMED IN A SPARK IGNITION GASOLINE-FUELED INTERNAL COMBUSTION ENGINE IS DISCLOSED. THE METHOD FEATURES THE USE OF GASOLINE CONTAINING A DEPOSIT REDUCING AMOUNT OF A HIGH MOLECULAR WEIGHT ALKYL AROMATIC HYDROCARBON OR MIXTURE OF ALKYL AROMATIC HYDROCARBONS. THE GASOLINE COMPOISTIONS AND GASOLINE ADDITIVE CONCENTRATES ARE ALSO DISCLOSED.

United States Patent 3,817,721 GASOLINE COMPOSITIONS Warren L. Perilstein, Orchard Lake, Mich., assignor to Ethyl Corporation, Richmond, Va.

No Drawing. Continuation-impart of abandoned application Ser. No. 828,753, May 28, 1969. This application Dec. 6, 1971, Ser. No. 205,359

Int. Cl. C101 1/16 US. Cl. 44-69 40 Claims ABSTRACT OF THE DISCLOSURE A method of reducing intake valve deposits formed in a spark ignition gasoline-fueled internal combustion engine is disclosed. The method features the use of gasoline containing a desposit reducing amount of a high molecular weight alkyl aromatic hydrocarbon or mixture of alkyl aromatic hydrocarbons.

The gasoline compositions and gasoline additive concentrates are also disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a Continuation-in-Part of copending application Ser. No. 828,753, filed May 28, 1969, now abandoned.

BACKGROUND OF THE INVENTION During the operation of a spark ignition internal combustion engine, deposits are formed on portions of the intake system. The intake system is that part of the engine before the combustion chamber (cylinder) through which the air-fuel mixture is conducted. These deposits are apparently residues formed when the fuel and/or lubricant oil used in the engine contact the hot surfaces within the intake system. The deposits which form on the intake valve stem and the side opposite the value face (underhead) are of special concern. Such deposits contribute to the intake valve failure by causing the valves to overheat for example; these deposits may also prevent proper seatting of the intake valves which would result in engine malfunction. Thus, it is desirable that the formation of these deposits be minimized.

Additives to prevent or reduce engine deposits are disclosed in the art; see US. 1,692,784, U.S. 2,066,234, US. 2,080,681, US. 2,103,927, and US. 2,725,942. One disadvantage of known additives is that relatively high concentrations are required for good effectiveness.

It has been discovered that a relatively small amount of a high molecular weight alkyl aromatic hydrocarbon such as an alkyl benzene or mixture of alkyl benzenes, is extremely effective as an additive in gasoline for preventing undesirable intake system deposits; and especially the aforesaid intake valve deposits.

SUMMARY OF THE INVENTION A method of reducing deposits formed on the intake valves of a spark ignition internal combustion engine by 3,817,721 Patented June 18, 1974 ice DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is directed to a method of improving spark ignition, internal combustion engine opera ation by reducing deposits formed in the intake system and especially on the underhead intake valve, by burning in said engine gasoline containing from about 50 to about 1000 parts per million (ppm) by weight of an additive which comprises alkyl aromatic hyrocarbons having (a) at least one C or longer alkyl group and (b) a molecular weight of at least about 400. Alkyl benzenes and mixtures of alkyl benzenes are preferred.

A more preferred method utilizes a mixture of alkyl benzenes having an average molecular weight of from about 600 to about 1000, with a 700-800 molecular weight being most preferred. In addition to the deposit reducing additive, the gasoline may also contain a suitable metalloorganic antiknock agent such as tetraethyllead, tetramethyllead, tetravinyllead, mixtures of these lead'compounds, (methylcyclopentadienyl), manganese tricarbonyl, and the like. This preferred gasoline may likewise contain a halohydrocarbon scavenger such as ethylene dichloride, ethylene dibromide, and the like.

Another embodiment of this invention is gasoline containing an intake valve deposit reducing amount of the aforesaid alkyl aromatic benzenes. A useful concentration of this additive in the gasoline is from about 50 to about 1000 parts per million by weight; gasoline containing to 800 parts per million of the alkyl aromatic hydrocarbon is preferred. A more preferred gasoline composition also contains a suitable metallo-organic antiknock agent and a halohydrocarbon scavenger.

In preparing the gasoline fuels of the present invention the alkyl aromatic hydrocarbon additive can be added directly to the gasoline; or the additive can be made up as a concentrate in a suitable inert diluent, if desired, and then added to the gasoline. This additive concentrate can also contain other gasoline additives such as metalloorganic antiknock agents, halohydrocarbon scanvengers, dyes, surface ignition suppressors such as organic phosphates, carburetor detergents, antioxidants such as bin-- are alkyl aromatic hyrocarbons and mixtures of alkyl" aromatic hydrocarbons. These hydrocarbons are characterized by (1) having an average molecular weight of 400 or higher, and (2) containing at least one alkyl group having 12 or more carbon atoms. The average molecular weights of useful alkyl aromatic hydrocarbons will generally range from about 400 to about 1200 or more. The alkyl groups may be linear or branched. Alkyl aromatic hydrocarbons include monoas well as polyalkyl compounds; the aromatic portion of the alkyl aromatic hydrocarbon includes benzenes such as benzene, toluene, diphenyl and the like as well as polynuclear (fused ring) benzenes such as the naphthalenes, fluorene, phenanthrene and the like.

Examples of useful mono and polyalkyl polynuclear benzenes are l-n-dodecylphenanthrene and the like.

Alkyl benzenes and polyalkylbenzenes are preferred alkyl aromatic hydrocarbons. Examples of such preferred hydrocarbons are:

n-triacontylbenzene hexacosyldiphenyl l-(2-hexy1-n-dodecyl)diphenyl 1,1'-di,1,3,5,7,9-pentamethyl-n-decy1)diphenyl 3-tetracosyldiphenyl n-docosylbenzene dotriacontylbenzene 1,6-di(2-butyl-n-decyl)benzene 1,2-didodecylbenzene 1-decyl-2,4-didodecylbenzene 1,2,4-trioctadecylbenzene 2-decyl-4-dodecyltoluene Z-hexacosyl-p-xylene 4-octacosyltoluene l-docosyldiphenyl 3,3'-diheptadecyldiphenyl l-methyl-1'-heneicosyldiphenyl 1,1',2-nonadecyldiphenyl 2,4,6-tridodecyl-1,3,5-trimethylbenzene 1,4-di(2-hexyl-n-octyl)benzene 6-eicosyl-1,3-dimethylbenzene 2,4-didocosy1-l-tert-butylbenzene l,1',3,3'-tetradocosyldiphenyl 4-dotriacontyl-1,2-dimethylbenzene 1-methyl-2,4,6-tri( 1,3,5,7-tetramethyl-n-octyl) benzene 1,3,5-triheneicosylbenzene 1-isopropyl-2,6-dioctadecylbenzene 1-octyl-4-heptacosylbenzene 1-pentyl-2,6-dihexadecylbenzene 4 1,4-dimethyl-2,6-ditridecylbenzene 2-dotriacosyl-l-methylbenzene and the like.

Another preferred alkyl aromatic hydrocarbon is the product obtained on alkylating an aromatic hydrocarbon with a suitable olefin or mixture of olefins. Any effective method for alkylating aromatic hydrocarbons can in general, be used. A convenient alkylation process is that commonly known as the Friedel-Crafts process. Basically, the Friedel-Crafts process involves the treatment of an aromatic hydrocarbon with an olefin or mixture of olefins in the presence of a strong Lewis acid catalyst such as the aluminum halides, BF HF, H P 0 FeCl SnCl 21101 and the like. Aluminum chloride and aluminum bromide are preferred catalysts. Generally, aromatic alkylation procedures such as the 'Friedel- Crafts process produce a mixture of monoas well as polyalkylated aromatic hydrocarbons. Although it can be separated into its components, the mixture without any separation is quite useful in the present invention. Examples of Friedel-Crafts alkylation procedures and products will be presented below.

The aromatic hydrocarbons which can be alkylated to produce additives of the present invention include the benzenes such as benzene, diphenyl, lower alkyl benzenes such as toluene, xylene, isopropylbenzene, C -C alkyl benzenes, C -C alkyl diphenyls and the like; as well as polynuclear (fused ring) benzenes such as naphthalene, methylnaphthalene, phenanthrene, indene, fluorene and the like. The benzenes are preferred aromatic hydrocarbons; benzene is a most preferred aromatic hydrocarbon.

Olefins having 12 or more carbon atoms are useful for alkylation. The olefins may be branched or linear, ozor internal olefins.

Examples of useful olefins are:

l-dodecene, l-hexadecene, 2-eicosene, triisobutylene,

propylene tetramer, B-pentadecene, l-tricontene, 2- dotriacontene, Z-tetracosene, 3-octacosene, 2-nonadecene, 4-heneicosene, 1,2-diethyl-1-decene, 3-ethyl-3-dodecene, 2-octyl-1-hexadecene mixtures thereof and the like.

Mono-olefins are preferred.

Mixtures of commercial olefins are preferred for the alkylation. These commercial olefins are mixtures obtained from processes such as Ziegler catalyzed ethylene and/or propylene polymerization; catalytic dehydrogenation of suitable parafi'ins, e.g. wax cracked parafiins, and other similar processes. These commercial olefin mixtures can vary widely in composition from a-mono olefins, through intermediate mixtures, to 100% internal mono olefins. The range of carbon chain lengths in these mixtures can also vary considerably. Both branched and linear olefins can be present in these mixtures. Useful mixtures can also contain up to 10% by weight of C -C olefins. Mixtures in which a-monoolefins predominate are preferred; by predominate is meant that more than 50% by weight of the olefin mixture is a-monoolefin.

Examples of useful preferred commercial mixtures are those having the following olefin compositions by weight: 30% C 40% C and 30% C 10% C 20% C C15, C13, C17 and C13; C9, C10, C11, C12, C13, C14 and C15; 1% C 1% C 2% C 15% C 21% C 24% C C13, C20, C22 and C24; C22 and C24; C25, C23 and C30; C23, C24, C25, C26, C27 and C28; C29, C30 C31, C32 and C33; C29, 5% C 10% C 12% C 18% C 30% C 15% C and 8% C and the like.

A more preferred commercial mixture of olefins is one containing even carbon numbered olefins, ranging from about C to about C the olefins are predominately amonoolefins. These mixtures can also contain small amounts of C C and C olefins as well as C and higher olefins. These more preferred olefins will be designated herein as C olefins or C mixtures. Examples of typical olefins are listed in the following table.

TABLE 1 012+ olefin mixtures Olefin carbon No., percent by weightz A B O D r4310.-- 1. 84 1. 40 2. 01 20. 39 16. 72 19. 40 0. 3 12. 15 9. 76 12. 59 26. 5 10. 65 8. 28 10. 97 58.0 6. 29 6. 34 8. 88 12. 9 4. 35 4. 43 5.15 3. 25 5. 59 6. 63 4. 38 7. 5O 7. 70 3. 51 6. 41 4. 78 2. 07 3. 69 2. 4O 1. 33 1. 25 0. 90 0. 38 0. 17 0. 08

Total olefins, percent 70. 21 72 81. 58 97.7

Total parafiins, percent Other by-produots, percent--. 2. 3 Olefin configuration, percent distnbutionz 3 a 69. 7 60. 6 Internal 30. 3 39. 3

1 Vapor phase chromatographic analym's. 2 Estimated. I Nuclear magnetic resonance analysis.

Most preferred commercial olefin mixtures are mixtures of predominantly a-monoolefins of even carbon number ranging from O -C Again, small amounts of olefins outside this range can also be present. These most preferred olefin mixtures will be referred to herein as 0 olefins or C olefin mixtures. A general composition range of these C olefins is set out in the following table:

Specific examples of C and olefin compositions are given in the following table.

TABLE 3 Cm olefin mixtures E F G H J K L Olefin carbon No.,

1 Vapor phase chromatographic analysis. 3 Nuclear magnetic resonance analysis.

As pointed out above, the additives useful in the present invention are prepared by alkylating aromatic hydrocarbons. The following examples illustrate alkylation processes which produce alkyl aromatic hydrocarbon products useful in the present invention. All parts are by weight unless otherwise specified. All molecular weights were determined by vapor phase osmometry. The C olefins utilized in these examples fall within the general composition set out in Table 2.

Example 1 A solution of parts of benzene and 600 parts of a C olefin mixture was placed into a suitable vessel, fitted with a stirrer; to this solution was added portionwise over a 20-minute period 30 parts of an anhydrous aluminum chloride. During this addition of aluminum chloride the temperature ranged between 30 and 65 C. (the solution was stirred during the addition). The reaction mixture was heated to 70 C. and stirred for two hours at this temperature. Then, about parts of a 10% HCl solution was added. About 100 parts of benzene were added to reduce the viscosity of the mixture; the reaction mixture was then washed with water until the washings were no longer acid to litmus. The washed product was stripped under vacuum on a steam bath. The product obtained was 605.4 parts of a yellow, slightly hazy liquid. The molecular Weight of the product was 799. The infrared spectrum of the product indicated that it contained a substantial portion of alkylated benzenes.

Example 2 Following the basic procedure of Example 1, 60 parts of benzene was reacted with 300 parts of the 0 olefin mixture, using 15 parts of AlCl catalyst for\ 5 hours at 70 C. The yield of product was 297 parts; the molecular weight was 792.

Example 3 Following the basic procedure of Example 1, 240 parts of benzene were reacted with 1250 parts of the C olefin mixture using 50 parts of AlCl catalyst at 70 C. for 2 hours. Total product yield was 1250 parts; the molecular weight was 772.

Similar results are obtained carrying out the process of Example 1 when aluminum bromide is used in place of the aluminum chloride.

Example 4 A solution of 1400 parts of C olefin mixture and 270 parts benzene were charged into a suitable vessel equipped with a stirrer. To this solution was added 16 parts of aluminum chloride in small portions over a 2-4 minute period (the solution was stirred during the addition). The mixture was then heated to 95 C. for 2 /2 hours with stirring; then about 200 parts of a 10% HCl solution was added. Benzene was added to reduce the viscosity and the solution was washed with 200 part portions of water until the washings were free of acid (litmus paper). The washed benzene solution was filtered through Celite and then stripped under vacuum. The yield was 946 parts of a clear yellow liquid having a molecular weight of 703.

Example 5 The process of Example 4 was repeated using the following amounts of reactants: 1340 parts of 018+ olefin mixture, 264 parts of benzene and 66 parts of aluminum chloride. This reaction yielded 1128 parts of a liquid product having a molecular weight of 774.

Similar results are obtained when diphenyl, toluene or tert-butyl benzene are used in place of the benzene in Examples 1-5. Aluminum bromide or BF is also used successfully as a catalyst in place of AlCl C olefin mixture E, G, and H also yield a satisfactory product in the processes of Examples 1-5.

7 Example 6 The following three alkylations were run using basically the same procedure as in Example 4.

Run A.1500 parts of a C olefin mixture was reacted with 300 parts of benzene using 75 parts of AlCl catalyst at a tempertaure of 70 C. for 2 hours. The product obtained was a clear yellow, oily liquid; the yield was 1411 parts; the molecular weight was 787. Infrared analysis showed the presence of a mixture of alkyl benzenes.

Run B.1500 parts of a C olefin mixture was reacted with 300 parts of benzene using 75 parts of AlCl catalyst at a temperature of 7074 C. for 2 hours. The product obtained was a clear yellow, oily liquid; the yield was 1389 parts; the molecular weight was 775. Infrared analysis showed the presence of a mixture of alkyl benzenes.

Run C.-1500 parts of a C olefin mixture was reacted with 304 parts of benzene using 76 parts of AlCl catalyst at a temperature of 70 C. for 2 hours. The product obtained was a clear yellow, oily liquid; the yield was 1488 parts; the molecular weight was 764. Infrared analysis showed the presence of a mixture of alkyl benzenes.

The products from Example 6, Runs AC were blended. The resulting blend has a molecular weight of about 775.

Example 7 A catalyst complex was prepared by adding 48 parts of tert-butyl chloride in 65 parts of benzene to 20 parts of anhydrous AlCl in a suitable vessel while anhydrous HCl was slowly swept through. To this was added dropwise, with vigorous stirring, a solution of 92.2 parts of naphthalene, 100.8 parts of C olefin mixture and 150 parts of benzene. The addition required 30 minutes; the reaction mixture was stirred for an additional 30 minutes at 30-40 C. The black reaction mixture was washed first with about 250 parts of 5% HQ, then four times with 125 parts of water; and then the reaction mixture was stripped under vacuum on a steam bath. Infrared analysis of the product at this point showed that some unreacted naphthalene remained. The product was then extracted six times with about 25 part portions of dimethylsulfoxide and then washed with water. The washed product was stripped under vacuum on a steam bath. The product yield was 114.2 parts of a dark, mobile liquid. The molecular weight of this product determined by vapor phase osmometery was 398. Infrared analysis of the product showed the presence of alklylated naphthalenes and substantially no unreacted naphthalene.

The basic procedure of Example 7 is described in U.S. 2,541,882.

Example 8 The procedure of Example 4 was used except that the amount of olefin was doubled (200 parts). Additionallyl after extraction with dimethylsulfoxide and water, the product was dried over Na SO and then it was finally stripped. The yield was 223 parts of a clear, brown, fairly mobile liquid; the molecular weight, by vapor phase 0smometry, was 432. Infrared analysis of the product showed the presence of alkylated naphthalene and the absence of unreacted naphthalene.

When substantially the same reaction as in Example 7 was run at 100 C. for 2 hours, without any benzene present during the reaction period, the product yield was 196.7 parts; the molecular weight of this product was 557. The product was substantially free of unreacted naphthalene. Infrared analysis showed the presence of alkylated naphthalenes.

Example 9 A mixture of 461 parts of naphthalene and 1225 parts of a C olefin mixture was placed into a suitable vessel; the mixture was heated until it became homogeneous. Anhydrous AlCl (81 parts) was added gradually to the reaction mixture at a rate that maintained the temperature at 70 C. for 6 hours. Then, about 300 parts of a 5% HCI solution was added. The product mixture was diluted with parts of benzene and washed with 250 parts portions of water until the washings were no longer acid to litmus. The solvent was stripped under vacuum and the unreacted naphthalene was removed by distillation at temperatures up to 200 C. and under 10 mm. pressure. The yield of liquid product was 1436 parts; the molecular weight was 647.

Similar results are obtained when phenanthrene, fiuorene, indene, or methylnaphthalene are used in place of the naphthalene. Catalysts which are also effective are BF SnCl and HF. The C olefin mixtures A and B, wax cracked olefin mixtures, heptadecene, and propylenetetramer also yield good results when used in place of the C olefins.

Useful alkylated aromatic hydrocarbons having an average molecular weight between 400 and about 1200 are also obtained from the reaction of (a) n-dodecene and tolueneusing aluminum bromide catalyst, (b) a mixture of 20% C13, C14, C15, C16, C17 Olefin-S and xylene using BF catalyst, (c) C Olefin Mixture A (see Table l) and 2-methylanthracene using H SO catalyst, (d) a mixture of C C C olefins and fluorene using HF catalyst, (e) 0 Olefin Mixture B (Table l) and phenanthrene using P 0 catalyst, and (f) wax cracked olefins and diphenyl using ZnCl catalyst.

In carrying out the Friedel-Crafts alkylation illustrated by the previous examples, the reactant ratio can be varied. Molar ratios of olefimaromatic hydrocarbon can range from about 1:1 to about 10:1; molar ratios of 2:1 to 10:1 are preferred.

Any suitable Friedel-Crafts catalyst can be used; aluminum chloride and aluminum bromide are preferred. Any suitable amount of the catalyst can be used. Molar ratios of the aromatic hydrocarbonzcatalyst can range from 1:1 to about 10:1; preferred aromatic hydrocarbonzcatalyst ratios are from about 4:1 to about 10: 1.

The Friedel-Crafts alkylation can be carried out at any suitable temperature. Ordinarily, the reaction is carried out at atmospheric pressure. When carried out at atmospheric pressure, the limiting reaction temperature is the boiling point of the lowest boiling reactant. Thus, for atmospheric pressure alkylation, temperatures can vary from as low as 30 C. up to the boiling point of lowest boiling reactant. If the reaction is carried out under pressures above atmospheric, the upper temperature limit is consequently raised.

The Friedel-Crafts alkylation reaction time is dependent to a certain extent on other parameters such as for example temperature, activity of the reactants, type of catalyst. Thus, the reaction time can be varied over a wide range. Reaction temperatures of from 15 minutes up to 24 hours can be used.

The Friedel-Crafts alkylation can be carried out, if desired, in the presence of a solvent which is inert for the purposes of the desired alkylation. Examples 7 and 8 illustrate such a solvent use. Other similar solvent systems can be used.

As pointed out above, any procedure for alkylating aromatic hydrocarbons, which produces alkyl aromatic hydrocarbons as characterized above, can be used. Thus, for example, Friedel-Crafts alkylation, utilizing, as alkylating agents, alkyl halides or alkanols corresponding in type to the olefins described above, can be used to make additives of the present invention.

In preparing gasoline compositions suitable for use in the present invention, any internal combustion engine gasoline base fuels may be used. Gasoline is generally a blend of hydrocarbons boiling from about 25 C. to about 225 C. which occur naturally in petroleum and suitable hydrocarbons made by thermal or catalytic cracking or reforming of petroleum. Hydrocarbon compositions of typical base gasolines are tabulated below; percentages are by volume.

TABLE 4 Base gasolines A B C D E F G H I Percent:

Aromatics 31.5 30 19.0 24.0 50 60 80 Olefinics 4.0 3 18.5 12.5 10 20 20 Saturates 64.5 67 62.5 63.5 50 90 100 10 In preparing the gasoline compositions used in the present invention the alkyl aromatic hydrocarbon additives may be added directly to the gasoline or they can be added as additive concentrates. Conventional gasoline blending processes and apparatus can be used. Following are examples of gasoline compositions of the present invention. All parts are by weight unless otherwise indicated.

Example 10 A gasoline composition was prepared by adding to base gasoline A 3.12 grams of lead per gallon as tetraethyllead, about 1.35 grams of ethylene dibromide scavenger per gallon, about 1.49 grams of ethylene dichloride scavenger per gallon, and 500 parts per million (p.p.m.) of reaction product of Example 1.

Example 11 A gasoline composition was prepared by adding to base gasoline B 3.15 grams of lead per gallon as tetraethyllead, about 1.43 grams of ethylene dibromide scavenger per gallon, about 1.51 grams of ethylene dichloride scavenger per gallon, and 250 p.p.m. of the reaction product of Example 5.

Example 12 A gasoline composition was prepared by adding to base gasoline B, 3.15 grams of lead per gallon as tetraethyllead, about 1.43 grams of ethylene dichloride per gallon, about 1.51 grams of ethylene dibromide per gallon and 1.1 grams (400 p.p.m.) of the reaction product of Example per gallon.

Example 13 A gasoline composition was prepared by adding to base gasoline B, 3.15 grams of lead per gallon as tetraethyllead, about 1.43 grams of ethylene dichloride per gallon, about 1.51 grams of ethylene dibromide per gallon and 1.1 grams (400 p.p.m.) of the reaction product of Example 4 per gallon.

The tetraethyllead, ethylene dibromide and ethylene dichloride were added to the gasolines of Examples -13 as a commercial antiknock fluid which also contains a small amount of an antioxidant, dye and diluent hydrocarbon.

Example 14 A series of gasoline compositions is prepared by adding 50 p.p.m., 100 p.p.m., 200 p.p.m., 700 p.p.m., 1000 p.p.m. of the product of Example 7 to each of base gasolines A through I.

Example 15 Another series of gasoline comositions is prepared by adding 1.0 grams of lead per gallon as a tetraethyllead, about 0.45 grams of ethylene dibromide and about 0.48 grams of ethylene dichloride to each of the Example 14 compositions.

Example 16 A gasoline composition was prepared by adding to base gasoline A, 3.12 grams of lead per gallon as tetraethyllead, about 1.35 grams of ethylene dibromide scavenger per gallon, about 1.49 grams of ethylene dichloride scavenger per gallon, and 100 p.p.m. of the product of Example 2.

Example 17 A gasoline composition is prepared by adding 50 p.p.m. of didodecylbenzene to base gasoline C.

10 Example 18 A gasoline composition is prepared by adding p.p.m. of the product to Example 7 to the "base gasoline B.

Example 19 A gasoline composition is prepared by adding 300 p.p.m. of the product of Example 8 to base gasoline D.

Example 20 A gasoline composition is prepared by adding 450 p.p.m. of the product of Example -9 to base gasoline E.

Example 21 A gasoline composition was prepared by adding to base gasoline B, 3.15 grams of lead per gallon as tetraethyllead, about 1.43 grams of lead per gallon of ethylene dibromide, about 1.51 grams of lead per gallon as ethylene dichloride, and 400 p.p.m. of the blend of products from Example 6, Runs A through C."

Example 22 A series of gasoline compositions is prepared by adding 450 p.p.m. of each of (a) dioctacosylbenzene, (b) mixed 0 alkyldiphenyl having a 1200 molecular weight, (0) 1,4,8-trieicosylfluorene, or (d) mixed C alkylnaphthalenes having a 900 molecular weight in each of base gasolines A throuugh J.

Example 23 Another series of gasoline compositions is prepared by adding about 3 grams of lead per gallon as a tetraalkyllead antiknock and organohalide scavengers in the same proportions as in Examples 10 and 11, to the compositions of Example 22.

Examples 10 through 23 illustrate, but do not limit the gasoline compositions of the present invention. In other words, suitable gasoline compositions can be prepared using the alkyl aromatic hydrocarbons disclosed herein in any gasoline in the proportions taught above.

As pointed out previously, the alkyl aromatic hydrocarbon additives can conveniently be added to the base gasoline in the form of concentrates or fluids. These additive fluids would contain sufficient alkyl aromatic hydrocarbon additive and any other gasoline additive desired in the finished gasoline, such as antiknock agents (tetraethyllead, tetramethyllead, (methylcyclopentadienyl)manganese tricarbonyl), halohydrocarbon scavengers, phosphate deposit modifiers, dyes, antioxidants, and the like. The exact composition of such additive fluids is determined by the physical characteristics of the materials such as compatability, solubility, and the like, as well as the concentration desired in the finished gasoline.

The intake system deposit reducing effect of the additives of the present invention was determined by testing in an engine. The test procedure involved running a standard 6-cylinder automobile engine on the gasoline fuel to be tested for a total of 60 hours on a severe intake valve deposit cycle. This cycle consisted of running the engine for 150 seconds at 2000 revolutions per minute (r.p.m.) followed by 40 seconds at 500 rpm. for a total of 60 hours. At the end of this 60 hour test run, the manifold and head assemblies of the engine were removed for inspection. The intake valves were removed, Weighed and photographed. The valves were then cleaned to remove all the accumulated deposits and reweighed. The total deposit weight Was obtained by subtracting the weight of the valves after they had been cleaned from the weight of the valves with the accumulated deposits. In this way, a direct measure of the efiect of an additive on intake valve deposit formation was obtained. In addition to this direct measurement, a cleanliness rating based on visual inspection of the intake system of the engine was also made. The rating was based on a visual observation of the carburetor throttle body, the intake riser, the hot spot, the branches and valve ports of the disassembled engine, the Coordinating Research Coun- 1 1 cil (CRC) rating scale found in the Varnish Rating Manual No. 9 and Sludge Rating Manual No. 10 was used as a base for assigning a numerical Cleanliness Index.

Following is the data obtained in a series of such engine tests.

T base gasoline A was added substantially the same amount of the same tetraethyllead/organohalide antiknock fluid (Motor Mix) as in the compositions of Examples -13.

3 Underhead.

8 Average of four runs.

4 50=clean.

As the data above clearly show the alkyl aromatic hydrocarbon additives of the present invention significantly reduce the intake valve deposits in an internal combustion engine. These additives result in intake valve underhead deposit reductions ranging from 65% up to 90%. The Cleanliness Index data also indicates that the entire intake system of the engine is benefited when about 400 p.p.m. or more of the present additives is used.

Comparable intake valve deposit reduction is obtained when the fuel compositions of the other examples (or any of the fuels containing the additives described herein) are used in an internal combustion engine.

Another series of intake valve deposit reduction tests were run to illustrate the eifect of the molecular weight of the alkyl aromatic additive on its eflectiveness as a deposit reducer. In this series of tests, the engine test procedure set out above was used, but the test cycle was reduced to 30 hours. The following Table contains the results obtained from this series of tests.

TAB LE 6 Efiect of additive molecular weight on deposit reduction Reduction Amount in intake in base MW. of valve Alkyl aromatic fuel, addideposits, Test additive p.p.m. 1 tive 3 percent 4 6 Example 1 500 799 72 7- Detergent bottoms 400 336 5 do 2, 000 336 7 1 This is a commercial alkylated aromatic mixture having an average molecular weight of 336.

3 The base fuel contained 3 m1. of a commercial tetraethyllead antiknock fluid known as Motor Mix.

! Average molecular weight.

4 Based on comparison with the leaded base fuel Without any additive;

N orn.-M.W.=average molecular weight.

The data clearly shows that alkylated aromatics having a molecular weight below about 400 are substantially ineffective in reducing underhead intake valve deposits. Comparing Test 6 with Test 7 we see that at comparable use concentrations (500 p.p.m./400 p.p.m.), in alkyl aromatic additive of molecular weight 799 reduced deposits by 72%, while an alkylated aromatic additive having a molecular weight of 336 effected no significant reduction in deposits (5%). Even at 2000 p.p.m. (Test 7), the 336 molecular weight alkyl aromatic additive showed substantially no deposit reducing activity (7% reduction).

As indicated above, the alkyl aromatics of the present invention can also be made up as concentrates with suitable dilutents. Generally, gasoline compatible diluents are preferred. Examples of suitable diluents are the hydrocarbons such as kersosene, heptane, hexane, nonane and other such alkanes, toluene, benzene, xylene or other such low molecular weight aromatics, and mixtures of these types of hydrocarbons. The amount of alkyl aromatic additive in these concentrates can vary from about 10 to about by weight. These concentrates can also contain other gasoline additives already described above. Use of these concentrates facilitates handling and metering of the additives.

The present invention is embodied as described above, in a gasoline composition, a novel gasoline additive concentrate, a novel reaction product, and a method of reducing intake system deposits in an internal combustion engine. These embodiments have been fully and properly described above. The invention is limited only within the spirit and scope of the following claims.

I claim:

1. A method of reducing deposit formation on the intake valves of a spark ignition gasoline-fueled internal combustion engine by burning in said engine gasoline containing from about 50 to about 1000 parts per million by weight of an additive which comprises an alkyl aromatic hydrocarbon having (a) at least one alkyl group containing 12 or more carbon atoms, and (b) an average molecular weight of at least about 400.

2. The method of claim 1 wherein said gasoline contains a lead antiknock agent and a halohydrocarbon scavenger.

3. The method of claim 1 wherein said alkyl aromatic hydrocarbon is alkyl polynuclear aromatic hydrocarbon.

4. The method of claim 1 wherein said hydrocarbon is alkyl benzene.

5. The method of claim 1 wherein said additive is a mixture of alkyl aromatic hydrocarbons prepared by alkylatin g an aromatic hydrocarbon selected from benzene, C -C alkyl benzene, diphenyl and C -C alkyl diphenyl, with a mixture containing predominantly a-monoolefins of even carbon number ranging from about C to about C said mixture of alkyl aromatic hydrocarbons having an average molecular weight of from about 400 to about 1200.

6. The method of claim 5 wherein said aromatic hydrocarbon is benzene and said molecular weight is from about 700 to about 800.

7. The method of claim 6 wherein said gasoline contains a lead antiknock agent and a halohydrocarbon scavenger.

8. The method of claim 6 wherein said a-monoolefins are of even carbon number ranging from about C -C 9. The method of claim 8 wherein the concentration of said additive is from about to about 800 parts per million by weight.

10. The method of claim 8 wherein the concentration of said additive is about 100 parts per million by weight.

11. The method of claim 8 wherein the concentration of said additive is about 250 parts per million by weight.

12. The method of claim 8 wherein the concentration of said additive is about 400 parts per million by weight.

13. The method of claim 8 wherein the concentration of said additive is about 500 parts per million by weight.

14. Gasoline containing from about 50 to about 1000 parts per million by weight of an additive which comprises alkyl aromatic hydrocarbons having (a) at least one alkyl group containing 12 or more carbon atoms, and (b) an average molecular weight of at least about 400.

15. The gasoline of claim 14 additionally containing lead antiknock agent and halohydrocarbon scavenger.

16. The gasoline of claim 14 wherein said alkyl aromatic hydrocarbons are alkyl polynuclear benzenes.

17. The gasoline of claim 14 wherein said alkyl aromatic hydrocarbons are alkyl benzenes.

18. The gasoline of claim 14 wherein said additive is a mixture of alkyl benzenes prepared by alkylating a benzene hydrocarbon selected from benzene, C -C alkyl benzenes, diphenyl, and C -C alkyl diphenyls with a mixture containing predominantly a-monoolefins of even carbon number ranging from about C -C said mixture of alkyl benzenes having an average molecular weight of from about 400 to about 1200.

19. The gasoline of claim 18 wherein said benzene hydrocarbon is benzene and said molecular weight is from about 700 to about 800.

20. The gasoline of claim 19 additionally containing lead antiknock agent and halohydrocarbon scavenger.

21. The gasoline of claim 19 wherein said a-monoolefins are of even carbon number ranging from about C C 22. The gasoline of claim 21 wherein the concentration of said additive is from about 100 to about 800 parts per million by weight.

23. The gasoline of claim 22 wherein the concentration of said additive is from about 100 to about 250 parts per million by weight.

24. The gasoline of claim 22 wherein the concentration of said additive is from about 400 to about 800 parts million by weight.

25. The gasoline of claim 22 wherein the concentration of said additive is from about 400 to about 800 parts per million by weight.

26. The gasoline of claim 22 wherein the concentration of said additive is from about 400 to about 500 parts per million by weight.

27. An additive concentrate containing about to about 95% by weight of an additive which comprises alkyl aromatic hydrocarbon having (a) at least one alkyl group containing 12 or more carbon atoms, and (b) an average molecular weight of at least 400, and gasoline compatible diluent.

28. The additive concentrate of claim 27 additionally containing lead antiknock agent and halohydrocarbon scavenger.

29. The additive concentrate of claim 27 wherein said alkyl aromatic hydrocarbon is alkyl polynuclear aromatic hydrocarbon.

30. The additive concentrate of claim 27 wherein said alkyl aromatic hydrocarbon is alkyl benzene.

31. The additive concentrate of claim 30 wherein said additive is a mixture of alkyl aromatic hydrocarbons prepared by alkylating aromatic hydrocarbon selected from benzene, C -C alkyl benzene, diphenyl, and C -C alkyl diphenyl with a mixture containing predominantly m-monoolefins of even carbon number ranging from about C to about C said mixture of alkyl aromatic hydrocarbons having an average molecular weight of from about 400 to about 1200.

32. The additives concentrate of claim 31 wherein said aromatic hydrocarbon is benzene and said molecular weight is from about 700 to about 800.

33. The additive concentrate of claim 32 additionally about O a-C23.

35. Gasoline containing from about 50 to about 1000 parts per million by weight of a product obtained from a process which comprises reacting (a) an aromatic hydrocarbon selected from benzene,

C C alkyl benzenes, diphenyl, C -C alkyl diphenyls, naphthalene, C -C alkyl naphthalenes, anthra cene, phenanthrene, fiuorene, and indene with (b) a mixture of even carbon number monoolefins ranging predominantly from about C to about C wherein at least 30% of the olefins have the vinyl m-olefin configuration, at least 30% of the olefins have the vinylidene a-olefin configuration, and the remaining olefins have internal olefin configurations (c) in the presence of a catalytic amount of a catalyst selected from AlCl and AlBr and GE,

(d) at reaction temperatures ranging from about 30 C. to the boiling point of the lower boiling of the two reactants (a) and (b),

said product having an average molecular weight of from about 400 to about 1200.

36. The gasoline of claim 35 wherein said aromatic hydrocarbon (a) is benzene, said olefin mixture (b) ranges predominantly from about C to about C said catalyst (c) is an aluminum halide, said reaction temperature (d) is about C. said product having an average molecular weight of from about 700 to about 800.

37. The gasoline of claim 36 wherein the concentration of said product is from about to about 1000 parts per million by weight.

38. The gasoline of claim 36 wherein the concentration of said product is from about 200 to about 800 parts per million by weight.

39. The gasoline of claim 36 wherein the concentration of said product is from about 400 to about 800 parts per million by weight.

40. The gasoline of claim 35 wherein the concentration of said product is from about 400 to about 800 parts per million by weight.

References Cited UNITED STATES PATENTS 2,066,234 12/1936 Sloane et a1 208-17 X 2,080,681 5/1937 Wilson et a1 44-80 X 2,404,340 7/ 1946 Zimmerman 260-671 B 2,527,529 10/ 1950 Cade 44-80 X 2,726,942 12/ 1955 Arkis et a1 44-58 X 3,037,850 6/1962 Wythe et al. 44-62 3,438,757 4/ 1969 Honnen et al. 44-58 DANIEL E. WYMAN, Primary Examiner Y. H. SMITH, Assistant Examiner US. Cl. X.R. 44-80 UNITED STATES PATENT OFFICE f CERTIFICATE OF CORRECTION,

Patent No. I D t d June- Inventor) v War'rvn l,. ls'rrr'i I stein It is certified that error appears in the above-identified patent and that said Lettera Patent are herebycorrected as shownvbelow:

' Column 1, line '58 second instance) "value" should be valve Column 2, line 53 f "phenoyls" should be phenols Column 3, n 2 "tetradecylandthracene" should be tetradecylanthracene Column lin 55 "c -e should be 0 -0 Column 4, line 64 (first instance) "l/ C should be 1 /0 0 Column 5, line 46 4 in the title under" Table 2 after the word "percent" add Distribution Cofllumn .ljj (Claim 32), line P "benzene" should be aromatic Column 1M (Claim 55), line 15 "01 should be 131% Signed and sealed this 17th day of September 1974.

(SEAL) Attest:

C. MARSHALL DANN Commissioner of Patents MCCOY M. GIBSON JR. Attesting Officer 

